1 //===-- DWARFContext.cpp --------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
11 #include "llvm/ADT/SmallString.h"
12 #include "llvm/ADT/StringSwitch.h"
13 #include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
14 #include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h"
15 #include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
16 #include "llvm/Object/MachO.h"
17 #include "llvm/Object/RelocVisitor.h"
18 #include "llvm/Support/Compression.h"
19 #include "llvm/Support/Dwarf.h"
20 #include "llvm/Support/ELF.h"
21 #include "llvm/Support/Format.h"
22 #include "llvm/Support/Path.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include <algorithm>
25 using namespace llvm;
26 using namespace dwarf;
27 using namespace object;
28 
29 #define DEBUG_TYPE "dwarf"
30 
31 typedef DWARFDebugLine::LineTable DWARFLineTable;
32 typedef DILineInfoSpecifier::FileLineInfoKind FileLineInfoKind;
33 typedef DILineInfoSpecifier::FunctionNameKind FunctionNameKind;
34 
dumpPubSection(raw_ostream & OS,StringRef Name,StringRef Data,bool LittleEndian,bool GnuStyle)35 static void dumpPubSection(raw_ostream &OS, StringRef Name, StringRef Data,
36                            bool LittleEndian, bool GnuStyle) {
37   OS << "\n." << Name << " contents:\n";
38   DataExtractor pubNames(Data, LittleEndian, 0);
39   uint32_t offset = 0;
40   while (pubNames.isValidOffset(offset)) {
41     OS << "length = " << format("0x%08x", pubNames.getU32(&offset));
42     OS << " version = " << format("0x%04x", pubNames.getU16(&offset));
43     OS << " unit_offset = " << format("0x%08x", pubNames.getU32(&offset));
44     OS << " unit_size = " << format("0x%08x", pubNames.getU32(&offset)) << '\n';
45     if (GnuStyle)
46       OS << "Offset     Linkage  Kind     Name\n";
47     else
48       OS << "Offset     Name\n";
49 
50     while (offset < Data.size()) {
51       uint32_t dieRef = pubNames.getU32(&offset);
52       if (dieRef == 0)
53         break;
54       OS << format("0x%8.8x ", dieRef);
55       if (GnuStyle) {
56         PubIndexEntryDescriptor desc(pubNames.getU8(&offset));
57         OS << format("%-8s", dwarf::GDBIndexEntryLinkageString(desc.Linkage))
58            << ' ' << format("%-8s", dwarf::GDBIndexEntryKindString(desc.Kind))
59            << ' ';
60       }
61       OS << '\"' << pubNames.getCStr(&offset) << "\"\n";
62     }
63   }
64 }
65 
dumpAccelSection(raw_ostream & OS,StringRef Name,const DWARFSection & Section,StringRef StringSection,bool LittleEndian)66 static void dumpAccelSection(raw_ostream &OS, StringRef Name,
67                              const DWARFSection& Section, StringRef StringSection,
68                              bool LittleEndian) {
69   DataExtractor AccelSection(Section.Data, LittleEndian, 0);
70   DataExtractor StrData(StringSection, LittleEndian, 0);
71   OS << "\n." << Name << " contents:\n";
72   DWARFAcceleratorTable Accel(AccelSection, StrData, Section.Relocs);
73   if (!Accel.extract())
74     return;
75   Accel.dump(OS);
76 }
77 
dump(raw_ostream & OS,DIDumpType DumpType,bool DumpEH)78 void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType, bool DumpEH) {
79   if (DumpType == DIDT_All || DumpType == DIDT_Abbrev) {
80     OS << ".debug_abbrev contents:\n";
81     getDebugAbbrev()->dump(OS);
82   }
83 
84   if (DumpType == DIDT_All || DumpType == DIDT_AbbrevDwo)
85     if (const DWARFDebugAbbrev *D = getDebugAbbrevDWO()) {
86       OS << "\n.debug_abbrev.dwo contents:\n";
87       D->dump(OS);
88     }
89 
90   if (DumpType == DIDT_All || DumpType == DIDT_Info) {
91     OS << "\n.debug_info contents:\n";
92     for (const auto &CU : compile_units())
93       CU->dump(OS);
94   }
95 
96   if ((DumpType == DIDT_All || DumpType == DIDT_InfoDwo) &&
97       getNumDWOCompileUnits()) {
98     OS << "\n.debug_info.dwo contents:\n";
99     for (const auto &DWOCU : dwo_compile_units())
100       DWOCU->dump(OS);
101   }
102 
103   if ((DumpType == DIDT_All || DumpType == DIDT_Types) && getNumTypeUnits()) {
104     OS << "\n.debug_types contents:\n";
105     for (const auto &TUS : type_unit_sections())
106       for (const auto &TU : TUS)
107         TU->dump(OS);
108   }
109 
110   if ((DumpType == DIDT_All || DumpType == DIDT_TypesDwo) &&
111       getNumDWOTypeUnits()) {
112     OS << "\n.debug_types.dwo contents:\n";
113     for (const auto &DWOTUS : dwo_type_unit_sections())
114       for (const auto &DWOTU : DWOTUS)
115         DWOTU->dump(OS);
116   }
117 
118   if (DumpType == DIDT_All || DumpType == DIDT_Loc) {
119     OS << "\n.debug_loc contents:\n";
120     getDebugLoc()->dump(OS);
121   }
122 
123   if (DumpType == DIDT_All || DumpType == DIDT_LocDwo) {
124     OS << "\n.debug_loc.dwo contents:\n";
125     getDebugLocDWO()->dump(OS);
126   }
127 
128   if (DumpType == DIDT_All || DumpType == DIDT_Frames) {
129     OS << "\n.debug_frame contents:\n";
130     getDebugFrame()->dump(OS);
131     if (DumpEH) {
132       OS << "\n.eh_frame contents:\n";
133       getEHFrame()->dump(OS);
134     }
135   }
136 
137   if (DumpType == DIDT_All || DumpType == DIDT_Macro) {
138     OS << "\n.debug_macinfo contents:\n";
139     getDebugMacro()->dump(OS);
140   }
141 
142   uint32_t offset = 0;
143   if (DumpType == DIDT_All || DumpType == DIDT_Aranges) {
144     OS << "\n.debug_aranges contents:\n";
145     DataExtractor arangesData(getARangeSection(), isLittleEndian(), 0);
146     DWARFDebugArangeSet set;
147     while (set.extract(arangesData, &offset))
148       set.dump(OS);
149   }
150 
151   uint8_t savedAddressByteSize = 0;
152   if (DumpType == DIDT_All || DumpType == DIDT_Line) {
153     OS << "\n.debug_line contents:\n";
154     for (const auto &CU : compile_units()) {
155       savedAddressByteSize = CU->getAddressByteSize();
156       const auto *CUDIE = CU->getUnitDIE();
157       if (CUDIE == nullptr)
158         continue;
159       unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset(
160           CU.get(), DW_AT_stmt_list, -1U);
161       if (stmtOffset != -1U) {
162         DataExtractor lineData(getLineSection().Data, isLittleEndian(),
163                                savedAddressByteSize);
164         DWARFDebugLine::LineTable LineTable;
165         LineTable.parse(lineData, &getLineSection().Relocs, &stmtOffset);
166         LineTable.dump(OS);
167       }
168     }
169   }
170 
171   if (DumpType == DIDT_All || DumpType == DIDT_CUIndex) {
172     OS << "\n.debug_cu_index contents:\n";
173     getCUIndex().dump(OS);
174   }
175 
176   if (DumpType == DIDT_All || DumpType == DIDT_TUIndex) {
177     OS << "\n.debug_tu_index contents:\n";
178     getTUIndex().dump(OS);
179   }
180 
181   if (DumpType == DIDT_All || DumpType == DIDT_LineDwo) {
182     OS << "\n.debug_line.dwo contents:\n";
183     unsigned stmtOffset = 0;
184     DataExtractor lineData(getLineDWOSection().Data, isLittleEndian(),
185                            savedAddressByteSize);
186     DWARFDebugLine::LineTable LineTable;
187     while (LineTable.Prologue.parse(lineData, &stmtOffset)) {
188       LineTable.dump(OS);
189       LineTable.clear();
190     }
191   }
192 
193   if (DumpType == DIDT_All || DumpType == DIDT_Str) {
194     OS << "\n.debug_str contents:\n";
195     DataExtractor strData(getStringSection(), isLittleEndian(), 0);
196     offset = 0;
197     uint32_t strOffset = 0;
198     while (const char *s = strData.getCStr(&offset)) {
199       OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
200       strOffset = offset;
201     }
202   }
203 
204   if ((DumpType == DIDT_All || DumpType == DIDT_StrDwo) &&
205       !getStringDWOSection().empty()) {
206     OS << "\n.debug_str.dwo contents:\n";
207     DataExtractor strDWOData(getStringDWOSection(), isLittleEndian(), 0);
208     offset = 0;
209     uint32_t strDWOOffset = 0;
210     while (const char *s = strDWOData.getCStr(&offset)) {
211       OS << format("0x%8.8x: \"%s\"\n", strDWOOffset, s);
212       strDWOOffset = offset;
213     }
214   }
215 
216   if (DumpType == DIDT_All || DumpType == DIDT_Ranges) {
217     OS << "\n.debug_ranges contents:\n";
218     // In fact, different compile units may have different address byte
219     // sizes, but for simplicity we just use the address byte size of the last
220     // compile unit (there is no easy and fast way to associate address range
221     // list and the compile unit it describes).
222     DataExtractor rangesData(getRangeSection(), isLittleEndian(),
223                              savedAddressByteSize);
224     offset = 0;
225     DWARFDebugRangeList rangeList;
226     while (rangeList.extract(rangesData, &offset))
227       rangeList.dump(OS);
228   }
229 
230   if (DumpType == DIDT_All || DumpType == DIDT_Pubnames)
231     dumpPubSection(OS, "debug_pubnames", getPubNamesSection(),
232                    isLittleEndian(), false);
233 
234   if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes)
235     dumpPubSection(OS, "debug_pubtypes", getPubTypesSection(),
236                    isLittleEndian(), false);
237 
238   if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames)
239     dumpPubSection(OS, "debug_gnu_pubnames", getGnuPubNamesSection(),
240                    isLittleEndian(), true /* GnuStyle */);
241 
242   if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes)
243     dumpPubSection(OS, "debug_gnu_pubtypes", getGnuPubTypesSection(),
244                    isLittleEndian(), true /* GnuStyle */);
245 
246   if ((DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo) &&
247       !getStringOffsetDWOSection().empty()) {
248     OS << "\n.debug_str_offsets.dwo contents:\n";
249     DataExtractor strOffsetExt(getStringOffsetDWOSection(), isLittleEndian(),
250                                0);
251     offset = 0;
252     uint64_t size = getStringOffsetDWOSection().size();
253     while (offset < size) {
254       OS << format("0x%8.8x: ", offset);
255       OS << format("%8.8x\n", strOffsetExt.getU32(&offset));
256     }
257   }
258 
259   if (DumpType == DIDT_All || DumpType == DIDT_AppleNames)
260     dumpAccelSection(OS, "apple_names", getAppleNamesSection(),
261                      getStringSection(), isLittleEndian());
262 
263   if (DumpType == DIDT_All || DumpType == DIDT_AppleTypes)
264     dumpAccelSection(OS, "apple_types", getAppleTypesSection(),
265                      getStringSection(), isLittleEndian());
266 
267   if (DumpType == DIDT_All || DumpType == DIDT_AppleNamespaces)
268     dumpAccelSection(OS, "apple_namespaces", getAppleNamespacesSection(),
269                      getStringSection(), isLittleEndian());
270 
271   if (DumpType == DIDT_All || DumpType == DIDT_AppleObjC)
272     dumpAccelSection(OS, "apple_objc", getAppleObjCSection(),
273                      getStringSection(), isLittleEndian());
274 }
275 
getCUIndex()276 const DWARFUnitIndex &DWARFContext::getCUIndex() {
277   if (CUIndex)
278     return *CUIndex;
279 
280   DataExtractor CUIndexData(getCUIndexSection(), isLittleEndian(), 0);
281 
282   CUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_INFO);
283   CUIndex->parse(CUIndexData);
284   return *CUIndex;
285 }
286 
getTUIndex()287 const DWARFUnitIndex &DWARFContext::getTUIndex() {
288   if (TUIndex)
289     return *TUIndex;
290 
291   DataExtractor TUIndexData(getTUIndexSection(), isLittleEndian(), 0);
292 
293   TUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_TYPES);
294   TUIndex->parse(TUIndexData);
295   return *TUIndex;
296 }
297 
getDebugAbbrev()298 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
299   if (Abbrev)
300     return Abbrev.get();
301 
302   DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);
303 
304   Abbrev.reset(new DWARFDebugAbbrev());
305   Abbrev->extract(abbrData);
306   return Abbrev.get();
307 }
308 
getDebugAbbrevDWO()309 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
310   if (AbbrevDWO)
311     return AbbrevDWO.get();
312 
313   DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0);
314   AbbrevDWO.reset(new DWARFDebugAbbrev());
315   AbbrevDWO->extract(abbrData);
316   return AbbrevDWO.get();
317 }
318 
getDebugLoc()319 const DWARFDebugLoc *DWARFContext::getDebugLoc() {
320   if (Loc)
321     return Loc.get();
322 
323   DataExtractor LocData(getLocSection().Data, isLittleEndian(), 0);
324   Loc.reset(new DWARFDebugLoc(getLocSection().Relocs));
325   // assume all compile units have the same address byte size
326   if (getNumCompileUnits())
327     Loc->parse(LocData, getCompileUnitAtIndex(0)->getAddressByteSize());
328   return Loc.get();
329 }
330 
getDebugLocDWO()331 const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() {
332   if (LocDWO)
333     return LocDWO.get();
334 
335   DataExtractor LocData(getLocDWOSection().Data, isLittleEndian(), 0);
336   LocDWO.reset(new DWARFDebugLocDWO());
337   LocDWO->parse(LocData);
338   return LocDWO.get();
339 }
340 
getDebugAranges()341 const DWARFDebugAranges *DWARFContext::getDebugAranges() {
342   if (Aranges)
343     return Aranges.get();
344 
345   Aranges.reset(new DWARFDebugAranges());
346   Aranges->generate(this);
347   return Aranges.get();
348 }
349 
getDebugFrame()350 const DWARFDebugFrame *DWARFContext::getDebugFrame() {
351   if (DebugFrame)
352     return DebugFrame.get();
353 
354   // There's a "bug" in the DWARFv3 standard with respect to the target address
355   // size within debug frame sections. While DWARF is supposed to be independent
356   // of its container, FDEs have fields with size being "target address size",
357   // which isn't specified in DWARF in general. It's only specified for CUs, but
358   // .eh_frame can appear without a .debug_info section. Follow the example of
359   // other tools (libdwarf) and extract this from the container (ObjectFile
360   // provides this information). This problem is fixed in DWARFv4
361   // See this dwarf-discuss discussion for more details:
362   // http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
363   DataExtractor debugFrameData(getDebugFrameSection(), isLittleEndian(),
364                                getAddressSize());
365   DebugFrame.reset(new DWARFDebugFrame(false /* IsEH */));
366   DebugFrame->parse(debugFrameData);
367   return DebugFrame.get();
368 }
369 
getEHFrame()370 const DWARFDebugFrame *DWARFContext::getEHFrame() {
371   if (EHFrame)
372     return EHFrame.get();
373 
374   DataExtractor debugFrameData(getEHFrameSection(), isLittleEndian(),
375                                getAddressSize());
376   DebugFrame.reset(new DWARFDebugFrame(true /* IsEH */));
377   DebugFrame->parse(debugFrameData);
378   return DebugFrame.get();
379 }
380 
getDebugMacro()381 const DWARFDebugMacro *DWARFContext::getDebugMacro() {
382   if (Macro)
383     return Macro.get();
384 
385   DataExtractor MacinfoData(getMacinfoSection(), isLittleEndian(), 0);
386   Macro.reset(new DWARFDebugMacro());
387   Macro->parse(MacinfoData);
388   return Macro.get();
389 }
390 
391 const DWARFLineTable *
getLineTableForUnit(DWARFUnit * U)392 DWARFContext::getLineTableForUnit(DWARFUnit *U) {
393   if (!Line)
394     Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
395 
396   const auto *UnitDIE = U->getUnitDIE();
397   if (UnitDIE == nullptr)
398     return nullptr;
399 
400   unsigned stmtOffset =
401       UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list, -1U);
402   if (stmtOffset == -1U)
403     return nullptr; // No line table for this compile unit.
404 
405   stmtOffset += U->getLineTableOffset();
406   // See if the line table is cached.
407   if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
408     return lt;
409 
410   // We have to parse it first.
411   DataExtractor lineData(U->getLineSection(), isLittleEndian(),
412                          U->getAddressByteSize());
413   return Line->getOrParseLineTable(lineData, stmtOffset);
414 }
415 
parseCompileUnits()416 void DWARFContext::parseCompileUnits() {
417   CUs.parse(*this, getInfoSection());
418 }
419 
parseTypeUnits()420 void DWARFContext::parseTypeUnits() {
421   if (!TUs.empty())
422     return;
423   for (const auto &I : getTypesSections()) {
424     TUs.emplace_back();
425     TUs.back().parse(*this, I.second);
426   }
427 }
428 
parseDWOCompileUnits()429 void DWARFContext::parseDWOCompileUnits() {
430   DWOCUs.parseDWO(*this, getInfoDWOSection());
431 }
432 
parseDWOTypeUnits()433 void DWARFContext::parseDWOTypeUnits() {
434   if (!DWOTUs.empty())
435     return;
436   for (const auto &I : getTypesDWOSections()) {
437     DWOTUs.emplace_back();
438     DWOTUs.back().parseDWO(*this, I.second);
439   }
440 }
441 
getCompileUnitForOffset(uint32_t Offset)442 DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
443   parseCompileUnits();
444   return CUs.getUnitForOffset(Offset);
445 }
446 
getCompileUnitForAddress(uint64_t Address)447 DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
448   // First, get the offset of the compile unit.
449   uint32_t CUOffset = getDebugAranges()->findAddress(Address);
450   // Retrieve the compile unit.
451   return getCompileUnitForOffset(CUOffset);
452 }
453 
getFunctionNameForAddress(DWARFCompileUnit * CU,uint64_t Address,FunctionNameKind Kind,std::string & FunctionName)454 static bool getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address,
455                                       FunctionNameKind Kind,
456                                       std::string &FunctionName) {
457   if (Kind == FunctionNameKind::None)
458     return false;
459   // The address may correspond to instruction in some inlined function,
460   // so we have to build the chain of inlined functions and take the
461   // name of the topmost function in it.
462   const DWARFDebugInfoEntryInlinedChain &InlinedChain =
463       CU->getInlinedChainForAddress(Address);
464   if (InlinedChain.DIEs.size() == 0)
465     return false;
466   const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
467   if (const char *Name =
468           TopFunctionDIE.getSubroutineName(InlinedChain.U, Kind)) {
469     FunctionName = Name;
470     return true;
471   }
472   return false;
473 }
474 
getLineInfoForAddress(uint64_t Address,DILineInfoSpecifier Spec)475 DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
476                                                DILineInfoSpecifier Spec) {
477   DILineInfo Result;
478 
479   DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
480   if (!CU)
481     return Result;
482   getFunctionNameForAddress(CU, Address, Spec.FNKind, Result.FunctionName);
483   if (Spec.FLIKind != FileLineInfoKind::None) {
484     if (const DWARFLineTable *LineTable = getLineTableForUnit(CU))
485       LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
486                                            Spec.FLIKind, Result);
487   }
488   return Result;
489 }
490 
491 DILineInfoTable
getLineInfoForAddressRange(uint64_t Address,uint64_t Size,DILineInfoSpecifier Spec)492 DWARFContext::getLineInfoForAddressRange(uint64_t Address, uint64_t Size,
493                                          DILineInfoSpecifier Spec) {
494   DILineInfoTable  Lines;
495   DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
496   if (!CU)
497     return Lines;
498 
499   std::string FunctionName = "<invalid>";
500   getFunctionNameForAddress(CU, Address, Spec.FNKind, FunctionName);
501 
502   // If the Specifier says we don't need FileLineInfo, just
503   // return the top-most function at the starting address.
504   if (Spec.FLIKind == FileLineInfoKind::None) {
505     DILineInfo Result;
506     Result.FunctionName = FunctionName;
507     Lines.push_back(std::make_pair(Address, Result));
508     return Lines;
509   }
510 
511   const DWARFLineTable *LineTable = getLineTableForUnit(CU);
512 
513   // Get the index of row we're looking for in the line table.
514   std::vector<uint32_t> RowVector;
515   if (!LineTable->lookupAddressRange(Address, Size, RowVector))
516     return Lines;
517 
518   for (uint32_t RowIndex : RowVector) {
519     // Take file number and line/column from the row.
520     const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
521     DILineInfo Result;
522     LineTable->getFileNameByIndex(Row.File, CU->getCompilationDir(),
523                                   Spec.FLIKind, Result.FileName);
524     Result.FunctionName = FunctionName;
525     Result.Line = Row.Line;
526     Result.Column = Row.Column;
527     Lines.push_back(std::make_pair(Row.Address, Result));
528   }
529 
530   return Lines;
531 }
532 
533 DIInliningInfo
getInliningInfoForAddress(uint64_t Address,DILineInfoSpecifier Spec)534 DWARFContext::getInliningInfoForAddress(uint64_t Address,
535                                         DILineInfoSpecifier Spec) {
536   DIInliningInfo InliningInfo;
537 
538   DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
539   if (!CU)
540     return InliningInfo;
541 
542   const DWARFLineTable *LineTable = nullptr;
543   const DWARFDebugInfoEntryInlinedChain &InlinedChain =
544       CU->getInlinedChainForAddress(Address);
545   if (InlinedChain.DIEs.size() == 0) {
546     // If there is no DIE for address (e.g. it is in unavailable .dwo file),
547     // try to at least get file/line info from symbol table.
548     if (Spec.FLIKind != FileLineInfoKind::None) {
549       DILineInfo Frame;
550       LineTable = getLineTableForUnit(CU);
551       if (LineTable &&
552           LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
553                                                Spec.FLIKind, Frame))
554         InliningInfo.addFrame(Frame);
555     }
556     return InliningInfo;
557   }
558 
559   uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
560   for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
561     const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
562     DILineInfo Frame;
563     // Get function name if necessary.
564     if (const char *Name =
565             FunctionDIE.getSubroutineName(InlinedChain.U, Spec.FNKind))
566       Frame.FunctionName = Name;
567     if (Spec.FLIKind != FileLineInfoKind::None) {
568       if (i == 0) {
569         // For the topmost frame, initialize the line table of this
570         // compile unit and fetch file/line info from it.
571         LineTable = getLineTableForUnit(CU);
572         // For the topmost routine, get file/line info from line table.
573         if (LineTable)
574           LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
575                                                Spec.FLIKind, Frame);
576       } else {
577         // Otherwise, use call file, call line and call column from
578         // previous DIE in inlined chain.
579         if (LineTable)
580           LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(),
581                                         Spec.FLIKind, Frame.FileName);
582         Frame.Line = CallLine;
583         Frame.Column = CallColumn;
584       }
585       // Get call file/line/column of a current DIE.
586       if (i + 1 < n) {
587         FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine,
588                                    CallColumn);
589       }
590     }
591     InliningInfo.addFrame(Frame);
592   }
593   return InliningInfo;
594 }
595 
consumeCompressedGnuHeader(StringRef & data,uint64_t & OriginalSize)596 static bool consumeCompressedGnuHeader(StringRef &data,
597                                        uint64_t &OriginalSize) {
598   // Consume "ZLIB" prefix.
599   if (!data.startswith("ZLIB"))
600     return false;
601   data = data.substr(4);
602   // Consume uncompressed section size (big-endian 8 bytes).
603   DataExtractor extractor(data, false, 8);
604   uint32_t Offset = 0;
605   OriginalSize = extractor.getU64(&Offset);
606   if (Offset == 0)
607     return false;
608   data = data.substr(Offset);
609   return true;
610 }
611 
consumeCompressedZLibHeader(StringRef & Data,uint64_t & OriginalSize,bool IsLE,bool Is64Bit)612 static bool consumeCompressedZLibHeader(StringRef &Data, uint64_t &OriginalSize,
613                                         bool IsLE, bool Is64Bit) {
614   using namespace ELF;
615   uint64_t HdrSize = Is64Bit ? sizeof(Elf64_Chdr) : sizeof(Elf32_Chdr);
616   if (Data.size() < HdrSize)
617     return false;
618 
619   DataExtractor Extractor(Data, IsLE, 0);
620   uint32_t Offset = 0;
621   if (Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Word)
622                                              : sizeof(Elf32_Word)) !=
623       ELFCOMPRESS_ZLIB)
624     return false;
625 
626   // Skip Elf64_Chdr::ch_reserved field.
627   if (Is64Bit)
628     Offset += sizeof(Elf64_Word);
629 
630   OriginalSize = Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Xword)
631                                                         : sizeof(Elf32_Word));
632   Data = Data.substr(HdrSize);
633   return true;
634 }
635 
tryDecompress(StringRef & Name,StringRef & Data,SmallString<32> & Out,bool ZLibStyle,bool IsLE,bool Is64Bit)636 static bool tryDecompress(StringRef &Name, StringRef &Data,
637                           SmallString<32> &Out, bool ZLibStyle, bool IsLE,
638                           bool Is64Bit) {
639   if (!zlib::isAvailable())
640     return false;
641 
642   uint64_t OriginalSize;
643   bool Result =
644       ZLibStyle ? consumeCompressedZLibHeader(Data, OriginalSize, IsLE, Is64Bit)
645                 : consumeCompressedGnuHeader(Data, OriginalSize);
646 
647   if (!Result || zlib::uncompress(Data, Out, OriginalSize) != zlib::StatusOK)
648     return false;
649 
650   // gnu-style names are started from "z", consume that.
651   if (!ZLibStyle)
652     Name = Name.substr(1);
653   return true;
654 }
655 
DWARFContextInMemory(const object::ObjectFile & Obj,const LoadedObjectInfo * L)656 DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj,
657     const LoadedObjectInfo *L)
658     : IsLittleEndian(Obj.isLittleEndian()),
659       AddressSize(Obj.getBytesInAddress()) {
660   for (const SectionRef &Section : Obj.sections()) {
661     StringRef name;
662     Section.getName(name);
663     // Skip BSS and Virtual sections, they aren't interesting.
664     bool IsBSS = Section.isBSS();
665     if (IsBSS)
666       continue;
667     bool IsVirtual = Section.isVirtual();
668     if (IsVirtual)
669       continue;
670     StringRef data;
671 
672     section_iterator RelocatedSection = Section.getRelocatedSection();
673     // Try to obtain an already relocated version of this section.
674     // Else use the unrelocated section from the object file. We'll have to
675     // apply relocations ourselves later.
676     if (!L || !L->getLoadedSectionContents(*RelocatedSection,data))
677       Section.getContents(data);
678 
679     name = name.substr(name.find_first_not_of("._")); // Skip . and _ prefixes.
680 
681     bool ZLibStyleCompressed = Section.isCompressed();
682     if (ZLibStyleCompressed || name.startswith("zdebug_")) {
683       SmallString<32> Out;
684       if (!tryDecompress(name, data, Out, ZLibStyleCompressed, IsLittleEndian,
685                          AddressSize == 8))
686         continue;
687       UncompressedSections.emplace_back(std::move(Out));
688       data = UncompressedSections.back();
689     }
690 
691     StringRef *SectionData =
692         StringSwitch<StringRef *>(name)
693             .Case("debug_info", &InfoSection.Data)
694             .Case("debug_abbrev", &AbbrevSection)
695             .Case("debug_loc", &LocSection.Data)
696             .Case("debug_line", &LineSection.Data)
697             .Case("debug_aranges", &ARangeSection)
698             .Case("debug_frame", &DebugFrameSection)
699             .Case("eh_frame", &EHFrameSection)
700             .Case("debug_str", &StringSection)
701             .Case("debug_ranges", &RangeSection)
702             .Case("debug_macinfo", &MacinfoSection)
703             .Case("debug_pubnames", &PubNamesSection)
704             .Case("debug_pubtypes", &PubTypesSection)
705             .Case("debug_gnu_pubnames", &GnuPubNamesSection)
706             .Case("debug_gnu_pubtypes", &GnuPubTypesSection)
707             .Case("debug_info.dwo", &InfoDWOSection.Data)
708             .Case("debug_abbrev.dwo", &AbbrevDWOSection)
709             .Case("debug_loc.dwo", &LocDWOSection.Data)
710             .Case("debug_line.dwo", &LineDWOSection.Data)
711             .Case("debug_str.dwo", &StringDWOSection)
712             .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
713             .Case("debug_addr", &AddrSection)
714             .Case("apple_names", &AppleNamesSection.Data)
715             .Case("apple_types", &AppleTypesSection.Data)
716             .Case("apple_namespaces", &AppleNamespacesSection.Data)
717             .Case("apple_namespac", &AppleNamespacesSection.Data)
718             .Case("apple_objc", &AppleObjCSection.Data)
719             .Case("debug_cu_index", &CUIndexSection)
720             .Case("debug_tu_index", &TUIndexSection)
721             // Any more debug info sections go here.
722             .Default(nullptr);
723     if (SectionData) {
724       *SectionData = data;
725       if (name == "debug_ranges") {
726         // FIXME: Use the other dwo range section when we emit it.
727         RangeDWOSection = data;
728       }
729     } else if (name == "debug_types") {
730       // Find debug_types data by section rather than name as there are
731       // multiple, comdat grouped, debug_types sections.
732       TypesSections[Section].Data = data;
733     } else if (name == "debug_types.dwo") {
734       TypesDWOSections[Section].Data = data;
735     }
736 
737     if (RelocatedSection == Obj.section_end())
738       continue;
739 
740     StringRef RelSecName;
741     StringRef RelSecData;
742     RelocatedSection->getName(RelSecName);
743 
744     // If the section we're relocating was relocated already by the JIT,
745     // then we used the relocated version above, so we do not need to process
746     // relocations for it now.
747     if (L && L->getLoadedSectionContents(*RelocatedSection,RelSecData))
748       continue;
749 
750     // In Mach-o files, the relocations do not need to be applied if
751     // there is no load offset to apply. The value read at the
752     // relocation point already factors in the section address
753     // (actually applying the relocations will produce wrong results
754     // as the section address will be added twice).
755     if (!L && isa<MachOObjectFile>(&Obj))
756       continue;
757 
758     RelSecName = RelSecName.substr(
759         RelSecName.find_first_not_of("._")); // Skip . and _ prefixes.
760 
761     // TODO: Add support for relocations in other sections as needed.
762     // Record relocations for the debug_info and debug_line sections.
763     RelocAddrMap *Map = StringSwitch<RelocAddrMap*>(RelSecName)
764         .Case("debug_info", &InfoSection.Relocs)
765         .Case("debug_loc", &LocSection.Relocs)
766         .Case("debug_info.dwo", &InfoDWOSection.Relocs)
767         .Case("debug_line", &LineSection.Relocs)
768         .Case("apple_names", &AppleNamesSection.Relocs)
769         .Case("apple_types", &AppleTypesSection.Relocs)
770         .Case("apple_namespaces", &AppleNamespacesSection.Relocs)
771         .Case("apple_namespac", &AppleNamespacesSection.Relocs)
772         .Case("apple_objc", &AppleObjCSection.Relocs)
773         .Default(nullptr);
774     if (!Map) {
775       // Find debug_types relocs by section rather than name as there are
776       // multiple, comdat grouped, debug_types sections.
777       if (RelSecName == "debug_types")
778         Map = &TypesSections[*RelocatedSection].Relocs;
779       else if (RelSecName == "debug_types.dwo")
780         Map = &TypesDWOSections[*RelocatedSection].Relocs;
781       else
782         continue;
783     }
784 
785     if (Section.relocation_begin() != Section.relocation_end()) {
786       uint64_t SectionSize = RelocatedSection->getSize();
787       for (const RelocationRef &Reloc : Section.relocations()) {
788         uint64_t Address = Reloc.getOffset();
789         uint64_t Type = Reloc.getType();
790         uint64_t SymAddr = 0;
791         uint64_t SectionLoadAddress = 0;
792         object::symbol_iterator Sym = Reloc.getSymbol();
793         object::section_iterator RSec = Obj.section_end();
794 
795         // First calculate the address of the symbol or section as it appears
796         // in the objct file
797         if (Sym != Obj.symbol_end()) {
798           Expected<uint64_t> SymAddrOrErr = Sym->getAddress();
799           if (!SymAddrOrErr) {
800             std::string Buf;
801             raw_string_ostream OS(Buf);
802             logAllUnhandledErrors(SymAddrOrErr.takeError(), OS, "");
803             OS.flush();
804             errs() << "error: failed to compute symbol address: "
805                    << Buf << '\n';
806             continue;
807           }
808           SymAddr = *SymAddrOrErr;
809           // Also remember what section this symbol is in for later
810           auto SectOrErr = Sym->getSection();
811           if (!SectOrErr) {
812             std::string Buf;
813             raw_string_ostream OS(Buf);
814             logAllUnhandledErrors(SectOrErr.takeError(), OS, "");
815             OS.flush();
816             errs() << "error: failed to get symbol section: "
817                    << Buf << '\n';
818             continue;
819           }
820           RSec = *SectOrErr;
821         } else if (auto *MObj = dyn_cast<MachOObjectFile>(&Obj)) {
822           // MachO also has relocations that point to sections and
823           // scattered relocations.
824           auto RelocInfo = MObj->getRelocation(Reloc.getRawDataRefImpl());
825           if (MObj->isRelocationScattered(RelocInfo)) {
826             // FIXME: it's not clear how to correctly handle scattered
827             // relocations.
828             continue;
829           } else {
830             RSec = MObj->getRelocationSection(Reloc.getRawDataRefImpl());
831             SymAddr = RSec->getAddress();
832           }
833         }
834 
835         // If we are given load addresses for the sections, we need to adjust:
836         // SymAddr = (Address of Symbol Or Section in File) -
837         //           (Address of Section in File) +
838         //           (Load Address of Section)
839         if (L != nullptr && RSec != Obj.section_end()) {
840           // RSec is now either the section being targeted or the section
841           // containing the symbol being targeted. In either case,
842           // we need to perform the same computation.
843           StringRef SecName;
844           RSec->getName(SecName);
845 //           llvm::dbgs() << "Name: '" << SecName
846 //                        << "', RSec: " << RSec->getRawDataRefImpl()
847 //                        << ", Section: " << Section.getRawDataRefImpl() << "\n";
848           SectionLoadAddress = L->getSectionLoadAddress(*RSec);
849           if (SectionLoadAddress != 0)
850             SymAddr += SectionLoadAddress - RSec->getAddress();
851         }
852 
853         object::RelocVisitor V(Obj);
854         object::RelocToApply R(V.visit(Type, Reloc, SymAddr));
855         if (V.error()) {
856           SmallString<32> Name;
857           Reloc.getTypeName(Name);
858           errs() << "error: failed to compute relocation: "
859                  << Name << "\n";
860           continue;
861         }
862 
863         if (Address + R.Width > SectionSize) {
864           errs() << "error: " << R.Width << "-byte relocation starting "
865                  << Address << " bytes into section " << name << " which is "
866                  << SectionSize << " bytes long.\n";
867           continue;
868         }
869         if (R.Width > 8) {
870           errs() << "error: can't handle a relocation of more than 8 bytes at "
871                     "a time.\n";
872           continue;
873         }
874         DEBUG(dbgs() << "Writing " << format("%p", R.Value)
875                      << " at " << format("%p", Address)
876                      << " with width " << format("%d", R.Width)
877                      << "\n");
878         Map->insert(std::make_pair(Address, std::make_pair(R.Width, R.Value)));
879       }
880     }
881   }
882 }
883 
anchor()884 void DWARFContextInMemory::anchor() { }
885